It is well known in the art to manufacture nanocomposites by polymerizing a polyamide monomer while in contact with a layered silicate material, e.g., a sodium smectite clay, that has been treated with a swelling agent, such as an onium ion, to form a nylon polymer-intercalated layered silicate dispersed in additional (non-intercalated) melted polymerized nylon (matrix polymer), e.g., see Toyota U.S. Pat. No. 4,739,007 (RE 37,385).
It is also well known in the nanocomposite art that nylon matrix polymers in nanocomposite compositions should have a number average molecular weight (Mn) that is relatively high, e.g., at least 20,000 in order to provide sufficiently high mechanical strengths (e.g., tensile strength and modulus of elasticity) and excellent thermal properties (e.g., high softening point and high temperature strengths, as well as other properties (e.g., see Toyota U.S. Pat. No. 4,739,007, Table 3).
Those skilled in the nanocomposite art have attempted to make a master batch or concentrate that includes a relatively high percentage of nylon-intercalated layered silicate material, e.g., 10% by weight or more layered silicate material, dispersed within a matrix polymer, without success. A primary difficulty in the melt-compounding manufacture of a nylon nanocomposite concentrate is that swelling agent-treated layered silicate materials have excellent compatibility with nylons, leaving little non-intercalated, melted nylon to enable sufficient flow (pumpability) of the composite material out of the compounder. Such concentrates frequently are in a relatively dry chunk or cake form, that adheres to reactor walls and compounder surfaces, having the nylon-intercalated clay unevenly dispersed within the little remaining excess, non-intercalated, nylon matrix polymer. Examples of required low percentages of layered silicate materials used in nylon-intercalated nanocomposite compositions are found in the Toyota U.S. Pat. No. 4,739,007 (5%) and Wolf Walsrode U.S. Pat. No. 5,994,445 (2%).